text: /*
   * vim:ts=4:sw=4:expandtab
   *
   * i3 - an improved dynamic tiling window manager
   * © 2009 Michael Stapelberg and contributors (see also: LICENSE)
   *
   * scratchpad.c: Moving windows to the scratchpad and making them visible again.
   *
   */
  #include "all.h"
  
  /*
   * Moves the specified window to the __i3_scratch workspace, making it floating
   * and setting the appropriate scratchpad_state.
   *
   * Gets called upon the command 'move scratchpad'.
   *
   */
  void scratchpad_move(Con *con) {
      if (con->type == CT_WORKSPACE) {
          LOG("'move scratchpad' used on a workspace \"%s\". Calling it "
              "recursively on all windows on this workspace.\n",
              con->name);
          Con *current;
          current = TAILQ_FIRST(&(con->focus_head));
          while (current) {
              Con *next = TAILQ_NEXT(current, focused);
              scratchpad_move(current);
              current = next;
          }
          return;
      }
      DLOG("should move con %p to __i3_scratch\n", con);
  
      Con *__i3_scratch = workspace_get("__i3_scratch", NULL);
      if (con_get_workspace(con) == __i3_scratch) {
          DLOG("This window is already on __i3_scratch.\n");
          return;
      }
  
      /* If the current con is in fullscreen mode, we need to disable that,
       *  as a scratchpad window should never be in fullscreen mode */
      if (focused && focused->type != CT_WORKSPACE && focused->fullscreen_mode != CF_NONE) {
          con_toggle_fullscreen(focused, CF_OUTPUT);
      }
  
      /* 1: Ensure the window or any parent is floating. From now on, we deal
       * with the CT_FLOATING_CON. We use automatic == false because the user
       * made the choice that this window should be a scratchpad (and floating).
       */
      Con *maybe_floating_con = con_inside_floating(con);
      if (maybe_floating_con == NULL) {
          floating_enable(con, false);
          con = con->parent;
      } else {
          con = maybe_floating_con;
      }
  
      /* 2: Send the window to the __i3_scratch workspace, mainting its
       * coordinates and not warping the pointer. */
      con_move_to_workspace(con, __i3_scratch, true, true, false);
  
      /* 3: If this is the first time this window is used as a scratchpad, we set
       * the scratchpad_state to SCRATCHPAD_FRESH. The window will then be
       * adjusted in size according to what the user specifies. */
      if (con->scratchpad_state == SCRATCHPAD_NONE) {
          DLOG("This window was never used as a scratchpad before.\n");
          if (con == maybe_floating_con) {
              DLOG("It was in floating mode before, set scratchpad state to changed.\n");
              con->scratchpad_state = SCRATCHPAD_CHANGED;
          } else {
              DLOG("It was in tiling mode before, set scratchpad state to fresh.\n");
              con->scratchpad_state = SCRATCHPAD_FRESH;
          }
      }
  }
  
  /*
   * Either shows the top-most scratchpad window (con == NULL) or shows the
   * specified con (if it is scratchpad window).
   *
   * When called with con == NULL and the currently focused window is a
   * scratchpad window, this serves as a shortcut to hide it again (so the user
   * can press the same key to quickly look something up).
   *
   */
  bool scratchpad_show(Con *con) {
      DLOG("should show scratchpad window %p\n", con);
      Con *__i3_scratch = workspace_get("__i3_scratch", NULL);
      Con *floating;
  
      /* If this was 'scratchpad show' without criteria, we check if the
       * currently focused window is a scratchpad window and should be hidden
       * again. */
      if (!con &&
          (floating = con_inside_floating(focused)) &&
          floating->scratchpad_state != SCRATCHPAD_NONE) {
          DLOG("Focused window is a scratchpad window, hiding it.\n");
          scratchpad_move(focused);
          return true;
      }
  
      /* If the current con or any of its parents are in fullscreen mode, we
       * first need to disable it before showing the scratchpad con. */
      Con *fs = focused;
      while (fs && fs->fullscreen_mode == CF_NONE)
          fs = fs->parent;
  
      if (fs && fs->type != CT_WORKSPACE) {
          con_toggle_fullscreen(fs, CF_OUTPUT);
      }
  
      /* If this was 'scratchpad show' without criteria, we check if there is a
       * unfocused scratchpad on the current workspace and focus it */
      Con *walk_con;
      Con *focused_ws = con_get_workspace(focused);
      TAILQ_FOREACH(walk_con, &(focused_ws->floating_head), floating_windows) {
          if (!con && (floating = con_inside_floating(walk_con)) &&
              floating->scratchpad_state != SCRATCHPAD_NONE &&
              floating != con_inside_floating(focused)) {
              DLOG("Found an unfocused scratchpad window on this workspace\n");
              DLOG("Focusing it: %p\n", walk_con);
              /* use con_descend_tiling_focused to get the last focused
               * window inside this scratch container in order to
               * keep the focus the same within this container */
              con_activate(con_descend_tiling_focused(walk_con));
              return true;
          }
      }
  
      /* If this was 'scratchpad show' without criteria, we check if there is a
       * visible scratchpad window on another workspace. In this case we move it
       * to the current workspace. */
      focused_ws = con_get_workspace(focused);
      TAILQ_FOREACH(walk_con, &all_cons, all_cons) {
          Con *walk_ws = con_get_workspace(walk_con);
          if (!con && walk_ws &&
              !con_is_internal(walk_ws) && focused_ws != walk_ws &&
              (floating = con_inside_floating(walk_con)) &&
              floating->scratchpad_state != SCRATCHPAD_NONE) {
              DLOG("Found a visible scratchpad window on another workspace,\n");
              DLOG("moving it to this workspace: con = %p\n", walk_con);
              con_move_to_workspace(walk_con, focused_ws, true, false, false);
              con_activate(con_descend_focused(walk_con));
              return true;
          }
      }
  
      /* If this was 'scratchpad show' with criteria, we check if the window
       * is actually in the scratchpad */
      if (con && con->parent->scratchpad_state == SCRATCHPAD_NONE) {
          DLOG("Window is not in the scratchpad, doing nothing.\n");
          return false;
      }
  
      /* If this was 'scratchpad show' with criteria, we check if it matches a
       * currently visible scratchpad window and hide it. */
      Con *active = con_get_workspace(focused);
      Con *current = con_get_workspace(con);
      if (con &&
          (floating = con_inside_floating(con)) &&
          floating->scratchpad_state != SCRATCHPAD_NONE &&
          current != __i3_scratch) {
          /* If scratchpad window is on the active workspace, then we should hide
           * it, otherwise we should move it to the active workspace. */
          if (current == active) {
              DLOG("Window is a scratchpad window, hiding it.\n");
              scratchpad_move(con);
              return true;
          }
      }
  
      if (con == NULL) {
          /* Use the container on __i3_scratch which is highest in the focus
           * stack. When moving windows to __i3_scratch, they get inserted at the
           * bottom of the stack. */
          con = TAILQ_FIRST(&(__i3_scratch->floating_head));
  
          if (!con) {
              LOG("You don't have any scratchpad windows yet.\n");
              LOG("Use 'move scratchpad' to move a window to the scratchpad.\n");
              return false;
          }
      } else {
          /* We used a criterion, so we need to do what follows (moving,
           * resizing) on the floating parent. */
          con = con_inside_floating(con);
      }
  
      /* 1: Move the window from __i3_scratch to the current workspace. */
      con_move_to_workspace(con, active, true, false, false);
  
      /* 2: Adjust the size if this window was not adjusted yet. */
      if (con->scratchpad_state == SCRATCHPAD_FRESH) {
          DLOG("Adjusting size of this window.\n");
          Con *output = con_get_output(con);
          con->rect.width = output->rect.width * 0.5;
          con->rect.height = output->rect.height * 0.75;
          floating_check_size(con, false);
          floating_center(con, con_get_workspace(con)->rect);
      }
  
      /* Activate active workspace if window is from another workspace to ensure
       * proper focus. */
      if (current != active) {
          workspace_show(active);
      }
  
      con_activate(con_descend_focused(con));
  
      return true;
  }
  
  /*
   * Greatest common divisor, implemented only for the least common multiple
   * below.
   *
   */
  static int _gcd(const int m, const int n) {
      if (n == 0)
          return m;
      return _gcd(n, (m % n));
  }
  
  /*
   * Least common multiple. We use it to determine the (ideally not too large)
   * resolution for the __i3 pseudo-output on which the scratchpad is on (see
   * below). We could just multiply the resolutions, but for some pathetic cases
   * (many outputs), using the LCM will achieve better results.
   *
   * Man, when you were learning about these two algorithms for the first time,
   * did you think you’d ever need them in a real-world software project of
   * yours? I certainly didn’t until now. :-D
   *
   */
  static int _lcm(const int m, const int n) {
      const int o = _gcd(m, n);
      return ((m * n) / o);
  }
  
  /*
   * When starting i3 initially (and after each change to the connected outputs),
   * this function fixes the resolution of the __i3 pseudo-output. When that
   * resolution is not set to a function which shares a common divisor with every
   * active output’s resolution, floating point calculation errors will lead to
   * the scratchpad window moving when shown repeatedly.
   *
   */
  void scratchpad_fix_resolution(void) {
      Con *__i3_scratch = workspace_get("__i3_scratch", NULL);
      Con *__i3_output = con_get_output(__i3_scratch);
      DLOG("Current resolution: (%d, %d) %d x %d\n",
           __i3_output->rect.x, __i3_output->rect.y,
           __i3_output->rect.width, __i3_output->rect.height);
      Con *output;
      int new_width = -1,
          new_height = -1;
      TAILQ_FOREACH(output, &(croot->nodes_head), nodes) {
          if (output == __i3_output)
              continue;
          DLOG("output %s's resolution: (%d, %d) %d x %d\n",
               output->name, output->rect.x, output->rect.y,
               output->rect.width, output->rect.height);
          if (new_width == -1) {
              new_width = output->rect.width;
              new_height = output->rect.height;
          } else {
              new_width = _lcm(new_width, output->rect.width);
              new_height = _lcm(new_height, output->rect.height);
          }
      }
  
      Rect old_rect = __i3_output->rect;
  
      DLOG("new width = %d, new height = %d\n",
           new_width, new_height);
      __i3_output->rect.width = new_width;
      __i3_output->rect.height = new_height;
  
      Rect new_rect = __i3_output->rect;
  
      if (memcmp(&old_rect, &new_rect, sizeof(Rect)) == 0) {
          DLOG("Scratchpad size unchanged.\n");
          return;
      }
  
      DLOG("Fixing coordinates of scratchpad windows\n");
      Con *con;
      TAILQ_FOREACH(con, &(__i3_scratch->floating_head), floating_windows) {
          floating_fix_coordinates(con, &old_rect, &new_rect);
      }
  }
  